Predicting Catalyst Extrudate Breakage Based on the Modulus of Rupture

Abstract

The mechanical strength of extruded catalysts and their natural or forced breakage by either collision against a surface or by a compressive load in a fixed bed are important phenomena in catalyst technology. The mechanical strength of the catalyst is measured here by its bending strength or flexural strength. This technique is relatively new from the perspective of applying it to commercial catalysts of typical sizes used in the industry. Catalyst breakage by collision against a surface is measured after a fall of the extrudates through the ambient air in a vertical pipe. Quantifying the impact force is done theoretically by applying Newton's second law. Measurement of catalyst breakage due to stress in a fixed bed is done following the standard procedure of the bulk crush strength test. Novel here is the focus on measuring the reduction in the length to diameter ratio of the extrudates as a function of the stress.

Ductile damage and fragmentation of highly porous γ-alumina under multi-point crushing test

“…As damageable behavior in porous ceramics is favored by high porosity rates [11,12], brittle fracture sometime is never observed and the determination of the tensile strength is no more possible. For this reason, the three-points bending test has been proposed to measure the tensile strength of brittle supports [5,13,14]. The bending strength of extrudates was recently used by Beeckman et al [15] to predict the reduction in the aspect ratio of extrudates due to brittle fractures in a fixed bed.…”